1. Field of the Invention
The present invention relates to an inspection jig to be used for nondestructive testing of an electronic circuit in an object under inspection which includes the electronic circuit therein.
2. Description of the Related Art
In a semiconductor integrated circuit mounted on electronic devices and the like, potential defects can be eliminated by performing various tests before mounting. The tests are performed in a non-destructive manner by application of voltage stress, operation under high temperature, storage under high temperature and the like corresponding to thermal and mechanical environment tests. Among various tests, as a test effective for rejecting an integrated circuit having initial operation failure, a burn in test, in which operation test is performed for a predetermined period under high temperature condition.
As shown in FIGS. 25 and 26, an inspection jig to be used in such burn in test includes a printed circuit board 2 arranged on a frame 6, is supplied a predetermined test voltage and having an input/output portion 2A outputting an abnormality detection signal indicative of shorting or other failure of an object under inspection, an object under inspection receptacle member 10 including a receptacle portion receiving a semiconductor integrated circuit as the object under inspection which is arranged at the predetermined position on the printed circuit board 2, which the receptacle portion receives a surface mounting QFP (quad flat package) type semiconductor element 12, for example, a cover member 8 having a contact portion 8a contacting with the upper surface of the semiconductor element 12 for depressing the latter with a predetermined pressure and covering the upper portion of the object under inspection receptacle member 10, and a hook member 16 engaging with both of the cover member 8 and the object under inspection receptacle member 10 for securing the cover member 8 on the object under inspection receptacle member 10.
One end portion of the cover member 8 is pivotably supported by a support shaft 10a provided on one edge portion of the object under inspection receptacle member 10 and thus is connected to the object under inspection receptacle member 10. By this, the cover member 8 is openably supported with respect to the object under inspection receptacle member 10 when the hook member 16 is in a condition disengaged from the cover member 8 and the object under inspection receptacle member 10.
On the other hand, in a portion of the internal surface side portion of the cover member 8 opposing to the semiconductor element 12, the contact portion 8a contacting with an outer shell of the semiconductor element 12 and downwardly depressing the latter with a predetermined pressure.
Respective terminals extending on every side from respective edges in the substantially square semiconductor element 12 loaded within the object under inspection receptacle member 10 are positioned in contact with respective connection terminals 2a of the printed circuit board 2. On the other hand, a portion of each connection terminal 2a contacting with the terminal of the semiconductor element 12 is formed into arc shaped configuration with elasticity.
Furthermore, each connection terminal 2a is connected to an input/output portion 2A via a printed wiring network which is neglected from illustration. By this, when the cover member 8 covers a receptacle chamber of the object under inspection receptacle member 10, each terminal of the semiconductor element 12 and each connection terminal 2a in the printing circuit board 2 are placed in electrically conducted state under action of a predetermined biasing force on each terminal in the semiconductor element 12.
With such construction, when the semiconductor element 12 is loaded within the object under inspection receptacle member 10, the cover member 8 is placed at closed condition and the hook member 16 is engaged to place each terminal of the semiconductor element 12 and each connection terminal 2a in the printing circuit board 2 in conducting state. Then, the predetermined testing voltage is supplied to the input/output portion 2A of the printed circuit board 2 to perform burn in test, for example.
When the tip end of each terminal and each connection terminal 2a in the printed circuit board 2 are contacted under the condition where a predetermined biasing force is acted on each terminal in the semiconductor device 12 as set forth above, since the cover member 8 is openably supported with respect to the object under inspection receptacle member 10, at first, the end edge portion of the contact portion 8a of the cover member 8 is contacted with a part of the upper surface as a depressed surface portion of the semiconductor element 12. And then, remaining contact surface in the contact portion 8a of the cover member 8 is contacted with other portion of the upper surface of the semiconductor element 12. In such case, when a part of the contact portion 8a is contacted on the outer shell of the semiconductor element 12 with offset, since the biasing force is not uniformly act on respective terminals, a shearing force may act on the contact surface between each terminal of the semiconductor element 12 and each connection terminal 2a of the printed circuit board 2 to possibly cause damage on the terminal of the semiconductor element 12 and to possibly cause difficulty in obtaining stable contacting state.
On the other hand, associating with increasing of density of the terminals of the semiconductor element 12, it is not easy to provide respective connection terminals 2a formed into arc shaped configuration and having elasticity, with a fine mutual interval on the printed circuit board 2 to cause high fabrication cost.